Ugandan Olympic athlete Rebecca Cheptegei has died after being set on fire by her boyfriend in Kenya, Uganda's Olympic Committee chief said on Thursday.

"We have learnt of the sad passing on of our Olympic athlete Rebecca Cheptegei... following a vicious attack by her boyfriend," Donald Rukare said in a post on X.

Cheptegei, 33, had sustained burns to 80 per cent of her body, the acting head of the Moi Teaching and Referral Hospital (MTRH) in the Rift Valley city of Eldorect where she was being treated, had told reporters on Tuesday.

"All her organs failed last night," a medic at the facility told AFP Thursday.

Police had said a man named as Dickson Ndiema Marangach, identified as her partner, had allegedly doused Cheptegei with petrol and set her alight in an attack on Sunday at her home in Endebess in the western county of Trans-Nzoia.

The incident took place just weeks after Cheptegei had taken part in the marathon at the Paris Olympics, where she placed 44th.

Kenyan media had reported that one of Cheptegei's daughters witnessed the assault at her mother's home.

"He kicked me while I tried to run to the rescue of my mother," Kenya's The Standard reported her as saying.

"I immediately cried out for help, attracting a neighbour who tried to extinguish the flames with water, but it was not possible," said the girl, who has not been named.

Marangach was also wounded in the incident, sustaining 30 per cent burns on his body.

The assault comes two years after Kenyan-born athlete Damaris Mutua was found dead in Iten, a world-famous running hub in the Rift Valley.

And in 2021, record-breaking Kenyan runner Agnes Tirop, 25, was found stabbed to death at her home in Iten in 2021. Her estranged husband is on trial over her murder. He has denied the charges.

Latest figures from the Kenya National Bureau of Statistics published in January 2023 found that 34 per cent of women in the country had experienced physical violence since the age of 15.